You can change any windows OS password without knowing current password.

Step1:Open Command Prompt (Run as administrator in windows vista/7/8) (In Windows XP you don't need to run as administrator)

How to Run as administrator??

[In search Box Type CMD, right click on this and there would be a option named "Run as administrator", click on and choose "Yes" to proceed further ]OR[In general, if you want to run any application as an administrator you can use "Ctrl+Shift+Left_click"]

Step2: Type "net user" without quotes and press enter it will show all the active accounts (e.g. Administrator,Guest,temp,etc..)

Step3: Now choose an account name for which you want to change password(let say you chose ABC account)

Step4: Type "net user ABC" without quotes and press enter, you'll see core details of your account. [NOTE: This step is just to verify whether you chose right account or not]

Step5: In last step you type " net user ABC * " without quotes and press enter[Note: after account name there is a single space and then a asterisk(AKA star) ]

Now it will ask for a new password :)enter desired password and re-enter for confirmation and You are DONE!!

[Note: when you type password you won't be able to see the password you r typing but it is actually happening, so don't worry about that but be careful about what you type (as you can see in below attached photo password is not visible to anyone even i cant see)]

Here is the screenshot of this process in Windows8.

in the same way you can disable/deactivate any user account.[Warn!!]Net user ABC /active:no Net user ABC /active:yes

Make folder name invisible(A folder Without name):select file or folder and rename it(Or press F2 as described above),clear current name now Hold "Alt" key and press 0160 from right side number keypad and now release the "Alt" key.[NOTE: Most of the modern laptop don't have right side number keypad so one way to do this is get a external keyboard or another shortcut is right click and choose "Insert unicode control character" option and then LRM(Left to right)]

Now all the reserved word can be used as a file/folder name which are not allowed in windows, e.g CON, AUX, NUL, LPT1, etc. Just PressALT+0160(described above) then type one of these reserved words

Wallpaper Changer

Wallpaper Changer is an android application developed to enhance their android mobile accessability. In this we can switch wallpaper automatically in a time period. So we can see everytime a fresh image that will refresh our minds to keep working freshly and tiredlessly .Hope everyone will get fun and getting interested in this application.

Beautiful & Immersive

Just say “Ok Google”

You don’t need to touch the screen to get things done. When on your home screen* or in Google Now, just say “Ok Google” to launch voice search, send a text, get directions or even play a song.

A work of art

While listening to music on your device, or while projecting movies to Chromecast, you’ll see beautiful full-screen album and movie art when your device is locked. You can play, pause, or seek to a specific moment.

Immerse yourself

The book you're reading, the game you're playing, or the movie you're watching — now all of these take center stage with the new immersive mode, which automatically hides everything except what you really want to see. Just swipe the edge of the screen to bring back your status bar and navigation buttons.

Faster multitasking

Android 4.4 takes system performance to an all-time high by optimizing memory and improving your touchscreen so that it responds faster and more accurately than ever before. This means that you can listen to music while browsing the web, or race down the highway with the latest hit game, all without a hitch.

Smart & Simple

Google smarts improve every corner of the Android experience.

The future is calling

The new phone app automatically prioritizes your contacts based on the people you talk to the most. You can also search for nearby places and businesses, your contacts, or people in your Google Apps domain.

A smarter caller ID

Whenever you get a call from a phone number not in your contacts, your phone will look for matches from businesses with a local listing on Google Maps.

All your messages in the same place

Never miss a message, no matter how your friend sends it. With the new Hangouts app, all of your SMS and MMS messages are together in the same app, alongside your other conversations and video calls. And with the new Hangouts, you can even share your location and send animated GIFs.

Emoji everywhere

Sometimes words can’t express how you feel. For that, there’s Emoji, the colorful Japanese characters, now available on Google Keyboard.

Grab & Go

New features help you get things done while you’re on the move.

Print wherever, whenever

Now you can print photos, documents, and web pages from your phone or tablet. You can print to any printer connected to Google Cloud Print, to HP ePrint printers, and to other printers that have apps in the Google Play Store.

Pick a file, any file

From apps like Quickoffice, you can open and save files on Google Drive, other cloud storage services, or your device. And with quick access to recently used files, it's easier than ever to send the file you were just working on.

Your office, anywhere

Create and edit documents, spreadsheets and presentations from your phone or tablet with the newly redesigned Quickoffice

Even more features

For those of you looking to go deeper, here's an exhaustive list of all the updates found in Android 4.4, KitKat.

This is the classic game of placing 8 queens on the chessboard, without one attacking another. Click on a square to place a queen. Re-click to remove the queen. This is harder than it initially seems, so may be useful. If you still can't solve it, you can ask the application to solve it for you.

Slide the numbers around until they are in numerical order from least to greatest, left to right and top to bottom.The white space is the open space that the numbered squares are moved to. To move a number, click on it. Only numbers that are immediately to the left, right, above or below the empty space can be moved. The open space should end up in the lower right hand corner when the puzzle has been solved..